Quote Originally Posted by banawe View Post
do you know higher octane ... means faster burn and more evaporation ... which means your gas burns faster gives you a little hp... and the gas evaporates faster when you are not using it ...

if you want more hp ... change the machine parts not the gas ... unless you dicided to buy a sportscar ...

BAS
regy
I'm sorry, but this is wrong. High octane does not burn faster, nor does it evaporate faster. It simply doesn't explode as easily as low octane.

Octane is resistance to detonation... which occurs when the compressed air-fuel mixture explodes by itself, without any igniting from the spark plug.

The higher the octane, the more you can compress the air-fuel mixture without premature detonation, and the more timing advance you can run.

More compression and timing advance = more power.

BUT... if you're running the same compression and timing, high octane = no gain.

On cars with a distributor, you can run higher octane, then advance your timing manually for a good 3-5 hp (for your basic 1.6 motor)... which often isn't much more than a little more "kick".

If you don't advance your timing, or if high octane doesn't allow you to advance it very much, you won't get any more power.

On EFI cars, some are tuned to take advantage of higher octane, this is felt as an extra kick when using V-Power or Blaze. Many cars with Japanese market tuning (95 Octane required) see some benefit. Conversely, some cars built to run on regular gas will actually lose some power on these high octane fuels, as they alter timing to adjust to them. Note, not all Japanese cars are tuned for 95 Octane... Some Hondas, for example, seem to thrive on lower Octane gasolines like XCS.

In other words... use whatever "feels" best. There's no single "best" gasoline for all cars.

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As for "regular" 81, I'd advise against it if you have a car built in the 90's or later. Most modern engines have relatively high compressions (usually 9.5:1 or 10:1) and may eat themselves if you use such piss-poor gas. You could experiment, but it'd be an expensive experiment if your car can't take it...